MIAMI — Not enough diabetic patients exercise, but even when they do, greater attention needs to be paid to how to best manage the effects of exertion on their type of disease, Dr. Dennis A. Cardone said at the annual meeting of the American Medical Society for Sports Medicine.
“More than 50% of diabetics are not meeting exercise goals,” said Dr. Cardone, who is in private practice at Pediatric Orthopedics of Southwest Florida in Fort Myers.
In the setting of type 1 diabetes, exercise can reduce the severity of microvascular complications and improve lipid profiles. And although there is no evidence that exercise prevents type 1 diabetes, it has been shown to prevent type 2 diabetes.
Dr. Cardone advises diabetics, regardless of their disease type, to use a bracelet or shoe tag that identifies them as diabetic, to exercise with a partner, and to bring snacks and a glucagon kit (complete with instructions on how to use it).
As far as making sure that type 1 disease is well managed during workouts, get a thorough history of what steps patients have taken while exercising in the past. “If they are newly diagnosed, have them do frequent monitoring of their glucose during an initial exercise regimen, and use that information for their exercise and diabetes management plan.” And obviously, patients need to choose their form of exercise wisely. “For risky sports, such as skydiving, scuba diving, climbing, and motor racing, it is common sense: If they have a hypoglycemic episode, the results could be disastrous,” Dr. Cardone said.
Marathon runners with type 1 diabetes are at increased risk of complications related to dehydration, Dr. Cardone said. Other risks involve their tendency toward peripheral and autonomic neuropathy. “You may recommend they check blood sugar every 6 miles,” but the reality is that management should be highly individualized and tailored to factors such as the frequency of hypoglycemic episodes.
Alcohol should be avoided 24 hours prior to exercise. Instruct type 1 patients to inject insulin about 1 hour before exercise at a nonexercising site, such as the abdomen. Drop short-acting insulin by 30% prior to exercising for 1 hour, by 40% for 2 hours, and by 50% for 3 hours, he suggested.
Avoid evening exercise to minimize risk of nighttime hypoglycemia. “Usually morning is the best time for exercise for type 1 diabetics, especially before the morning dose of insulin,” Dr. Cardone said.
“The general rule is that if glucose is greater than 250 before exercise, it is better to hold off until their number lowers. If glucose is less than 100, supplement before exercising,” he said.
The most effective combination for type 1 diabetics is insulin lispro plus Ultralente, Dr. Cardone said. It is easier to control blood sugar while exercising. The literature supports a good response, especially in high-level athletes, he said.
For the nondiabetic athlete, glucose falls off slowly over time but stays within a therapeutic range. In contrast, “glucose can be all over the place” for the exercising diabetic, Dr. Cardone said. Instruct patients to monitor glucose, hydrate, and increase caloric intake 12–24 hours after exercise, he said.
Causes of hypoglycemia include too much preexercise insulin, increased absorption from the injection site, inadequate caloric intake, and spontaneous activity.
“Most of the athletes with diabetes who become hypoglycemic run into problems after exercise, up to 24 hours after activity. They don't have the mechanism to shut off endogenous insulin.” Whole milk and sports drinks can be effective prevention, he added.